Radiological assessment of tumor response remains a challenge in patients treated with immune checkpoint inhibitors. In metastatic melanoma, for example, a spectrum of imaging response patterns to immunotherapies have been recognized and associated with clinical benefit. In metastatic renal cell carcinoma (mRCC), less than half of patients treated with immune checkpoint inhibitors achieve objective responses, but some of the responses have been durable. In this series, five different imaging patterns of response and progression are described mRCC patients treated with anti-PD-1/PD-L1 agents: 1) early and complete response, 2) pseudo-progression, 3) disease stability before ultimate response, 4) mixed response with new lesions, and 5) early progression/primary refractory disease. The implications of the different imaging patterns of response on prognosis are discussed and highlight the need for individualized patient assessment with the use of novel immune-targeted agents.
- Received August 10, 2015.
- Revision received September 4, 2015.
- Accepted September 21, 2015.
- Copyright © 2015, American Association for Cancer Research.